Atmospheric curing of isobutylenediolefin copolymers



Patented Aug. 15, 1950 "UNITED STATES PATENT OFFICE ATMOSPHERIC CURING or ISOBUTYLENE- DIOLEFIN COPOLYMERS Francis P. Baldwin, Linden, N. J., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application March 27, 1946,

Serial No. 657,619

without danger of scorching during the process.

This reduction in the tendency toward scorchiness is realized particularly in the use of aromatic estersoiquinone dioxime; but the use of aliphatic esters is also valuable in the fact that they show a good increase in solubility in solvents for the hydrocarbon polymer, as compared, for example,

with paraquinone dioxime itself. Thus, the aliphatic esters are particularly useful for the preparation of dipped goods where the question of scorchiness does not enter, but where the question of solubility is paramount; and the aromatic esters show both a good increase in solubility and a very good reduction in tendency toward scorchiness, thereby greatly facilitating both the dispersion of the curing agent in the. rubber com.- pound and greatly reducing the dii'liculties of milling and compounding as well as yielding a very smooth homogeneous mixture which cures particularly well. I

There is. however, a limit to the use of the quinone dioxime esters as curing agents because of the fact that curing cannot be accomplished at atmospheric pressure-or without the presence of a confining mold. In the case of the curing of rubber-coated fabrics and dipped goods, the rubber is not confined in a mold and a method of curing such goods under normal atmospheric conditions is highly desirable. In accordance with the present invention it has been found that the quinone dioxime esters may be employed as curing agents under atmospheric curing conditions if there is added to the compounded rubber mixture containing the esters a minor proportion of an oxide of lead of the type of ,PbO or one of its hydrates (sometimes called hydroxides of lead) such as PbOl-IzO, (PbO)2.I-I2O, (PbO)3,I-I2O, and the like. When such substances are added to the rubber mix, very satisfactory cures may be accomplished by curing the rubbermaterial in an oven in the resence of air.

The primary raw material'for the production of a synthetic rubber-like product of the present invention is the product of the interpolymeriza 4 Claims. (01. zen-85.3)

tion of a polymerizable olefin of not more than 8 carbon atoms and a diolefin of 4. to 14 carbon atoms per molecule. More particularly, the ill-' vention applies to the low temperature interpolymer of isobutylene and a diolefin.

The low temperature interpolymer is custo-g marily prepared by a low temperature catalysis.

The raw material for this polymer preferably con:

sists of a major proportion of isobutylene with;

a minor proportion of a polyolefin such as butadiene, isoprene, piperylene, dimethyl,

to 12 or 14 carbon atoms per molecule being usable. The preferred proportions range, from;-

parts of isobutylene with 30 parts of the diolefin to 99.5 parts of isobutylene with 0.5 part: The mixture is cooled to a" of the polyolefin. temperature within the range between approxl'r;

mately -20 and C., the preferred range being between 50 and -100 C. The cooling may be obtained by a refrigerating jacket on the". storage container or polymerization reactor, or,

by the admixture into the olefinic material of a carbonaceous refrigerant. For internal refrig-J erant of this type, such substances as liquid ethyl ene, liquid propane. solid or liquid carbon dioxide;

and the like are particularly useful. Other substances such as liquid methane under pressurefi if desired, or liquid butane under vacuum, if de-i sired, are also usable.

The cold mixture is polymerized by the a plication thereto of a Friedel-Crafts catalyst-of a type depending upon the particular olefinj'tofi be polymerized. The preferred catalyst is a so-" lution of a Friedel-Crafts catalyst such as aluminum chloride in solution in a low-freezing ',f non-complex-forming solvent such as ethyl or methyl chloride or carbon disulfide, or the like.

The Friedel-Crafts catalyst may be substan-f tially any of the substances disclosed by N. Q5; Galloway in his article on the Friedel-Crafts Synthesis printed in the issue of Chemical Re-' ing particularly well shown on page 375. The catalyst may be a simple salt or maybe one or another of a wide range of double salts depend-Q: 'ing upon the solvent it is desired to u'se and the rate of speed at which the polymerization is to occur.

The catalyst solvent depends to a considerable extent upon the choice of metal halide to'- be used. If the metal halide is to be aluminum' bu,- j tadiene, dimethallyl, myrcene, or thelike, sub;- stantially any of the polyolefins having from ,4,-

in the order given. In these tables the amounts of the various ingredients :are shown .as parts pen-100 parts-oi polymer.-- i.

6 The datashown in the above tables clearly indicate that the compounds PhD and its hydrate are outstandingly effective in promoting cures Table 1(a) I (Jo-polymer I 100.0 1 100.0 100.0 100.0 Steanc Acid 3.0 .Y 3.0 3.0 Carbon Blar-k 54.0 54.0 .54. 0 54:0 galgqumone Dioxime Dibenzoate 6. 0 6.0 .6. 0 6.0 H 5 0 5.0 5-6 PbOL... TensileMod-..at 300%E1ong.:

' 60 mun/250 F 0-0-1, 100+ 1, 210-680-580 1,.110-410-600 1, 020-400-710 1, 030-680-570 390-160-880 Press. Cured 120 m n/250 F. 60-0-1, 100+ 1, 210-700-540 1, 230-610-550 1, 040-520-690 920-730-440 1, 030-510-590 V 180 m1n. /250 F. 60-0-1, 100+ 1, 100-710-520 1, 220-630-530 1, 030-550-660 960-710-440 980-610-510 Y. i .60 1311111250 F. 0-0-1,100+ 0-0-1,100+ 0-01,l00+ 920-120-760 0-0-1, 000-]- 00l,100+ ,Air Oven Cured 120 m n/250 F. 0-0-1, 100+ 0-0-1,100+ 0-0-1, 100+ 870-230-560 0-0-1, 000+ 0-0-1,100+ 180 min/250 B (Hi-1,000+ 0-0-1, 100+ 0-0-1,100+ 910-340-600 0-0-1, 100-[- 001,100+

I Table I(b) Co-polymeni, 1000 100.0 100.0. Steam Acid" 3.0 3.0 3. 0 Carbon Black 54.0 54. 0 54. 0' Paraquinone 6. 0 6. 0 6. 0 C1120. 5.0 Cu0 5 0 HgO- B1(OH); Tensile-Mod. at 300%-Elong.:

60 min./250 F Poor Cures Poor Cures 1, 210-030-610 1,090-330-670 Poor Cures 1, 070-360-590 50-0-1,100+ Press. Cured 120 min/250 F. 1, 200-640-610 1, 140-530-610 1, 090-450-580 120-601,100+ 180 min/250 F 1, 130-640-540 1, 230-550-690 1, 070-470-570 200-90-1, 100+ 60 min/250 F. 0-0-1, 100-{- 0-0-1, 100+ 1. 220-140-720 0-0-1, 100-l- 0-0-1, 100+ 920-400-490 130-130-1,100+ Air Oven Cured 120 min./250 F. 0-0-1, 100+ 0-0-1, 100+ 1, 080-270-1, O80 0-0-1,100+ 0-0-1, 100+ 1, 070-590-490 120-120-1, 100+ 180 min/250 F. 0-0-1,100+ 0-0-1, 100+ 040-270-670 130-0-740 0-0-1, 100+ 930-610-430 0-01,050

EXAMPLE 2 Table II 100. 0 100.0 3.0 3. 0 54. 0 54.0 Paraquinone Dioxime Dibenzatte. 6.0 6. 0 (PbO)z'.'HzO 5. 0 10.0 Tensile-Elong.-Mod. at 300%:

min./250 F 1, 070-590-360 770-660-190 Press. Cured 120 min/250 F 1, 090-580-450 1 050-640-420 180 min/250 F 1, 070-570-470 1, 060-590-430 60 min/250 F- 920-490-400 990-500-500 1, All Oven Cured 120 min/250 F. 1,060-490-590 1, 060-460-590 180 min./250 F. 930-430-6110 990-440-630 EXAMPLE 3 v In this example the materials employed were the same as in Example 2 except that comparisons were made of the efiect of two different proportions of PhD instead of (PbO)2.H2O. Similar tests were made of the products. The results are shown in Table III, in which the tensile strength, modulus at 300% elongation and ultimate elongation of the product are shown in this order.

Table III (lo-polymer 100. 0 100. 0 Stearic A01 0. 3.0 3.0 Carbon Black 54.0 54.0 Paraquinone Dioxime Dibenzoate 6. 0 6.0 Pb 2. l5 5. 0

Tensile-Mod. at 300%-E1on 60 min. 250 F..- 1, 050-380-650 940-160-880 Press Cured..." 120 min/250 F 1,110-450-640 1, 060-270-790 180 Inin./250 F 1,110-420-610 1, 000-340-700 60 min/250 F... 1, 000-390-550 1, 140-300-710 Air Oven Cured. 120 min/250 F 1,060 490-550 1, 080-510-650 180 min/250 F 1, 050-480-530 980-610-540 with p-quinone dioxime dibenzoate when the curing is conducted in an air oven.

While there are described above but a limited number of embodiments of the present invention, it is possible to produce still other embodiments without departing from the inventive concept herein disclosed, and it is accordingly desired that the invention be considered as limited solely by the terms of the appended claims.

I claim:

1. An improved process for curing a rubbery synthetic interpolymer of isobutylene with a diolefin having from 4 to 14 carbon atoms per molecule, comprising the steps in combination of adding to the said interpolymer from 0.2 part to 10 parts of a p-quinone dioxime ester curing agent per of polymer and from 1 to 20 parts of a lead and oxygen containing compound selected from the class consisting of P100 and its hydrates per 100 parts of polymer and thereafter heating the material to curing temperature in a curing oven in the presence of air at atmospheric pressure for an appropriate curing time.

2. An improved process for curing a rubbery synthetic interpolymer of isobutylene with isoprene, comprising the steps in combination of adding to the said interpolymer from 0.2 part to 10 parts of a p-quinone dioxime ester curing agent per 100 of polymer and from 1 to 20 parts of a lead and oxygen containing compound selected from the class consisting of PhD and its hydrates per 100 parts of polymer and thereafter heating the material to curing temperature in a T curingaoven in thepresenceof a-irat atmospheric pressure 013.11 ta ppropriate curing time.

3. lAnei-m preved process fior curing a -rubbery synthetic interpolymer of isobutylene with isoprene, comprising the steps in combination adding to the said interpolymerirom 0.2 ,part

to 10 parts '-:of a p-quinone dioxime ester with :benzoic acifi'f-curing agent per 1000f polymerand from 1 to 20 parts of allead and oxygen containing compound selected from the lass consisting "of'PbO and its hydrates per 100 parts of polymer and thereafter heating the material to curing temperature ---a curing oven the presenne "of air fat i-satmospheri'c pressure for an appropfiate curing Etime.

{.An imp-rovedproce'ss for cur'ingia rubbery synthetic interpolymer of isobutylene withisO- prene, comprising the steps in combination or adding to the said interipolymer ffrom 0.2-pert telfial to curing temperature in a curing oven in the presence of air at atmospheric pressure for an appropriate curing time v FRANCIS VP.

REFERENCES CITED The following references are of .record .in the.

file of this patent:

UNITED STATES-PATENTS Number Name Date -i2,17o;191 Fisher i v., s Aug. 22, 1939 23912142 Roberts s Dec."25,1'945 f?t,.'393,321 Haworth Jan. 22, 1946 2,395,506 Sauser Feb. 26, 1946 

1. AN IMPROVED PROCESS FOR CURING A RUBBERY SYNTHETIC INTERPOLYMER OF ISOBUTYLENE WITH A DIOLEFIN HAVING FROM 4 TO 14 CARBON ATOMS PER MOLECULE, COMPRISING THE STEPS IN COMBINATION OF ADDING TO THE SAID INTERPOLYMER FROM 0.2 PART TO 10 PARTS OF A P-QUINONE DIOXIME ESTER CURING AGENT PER 100 OF POLYMER AND FROM 1 TO 20 PARTS OF A LEAD AND OXYGEN CONTAINING COMPOUND SELECTED FROM THE CLASS CONSISTING OF PBO AND ITS HYDRATES PER 100 PARTS OF POLYMER AND THEREAFTER HEATING THE MATERIAL TO CURING TEMPERATURE IN A CURING OVEN IN THE PRESENCE OF AIR AT ATMOSPHERIC PRESSURE FOR AN APPROPRIATE CURING TIME. 